Ding Liren thought for a long time on this move, an idea that changes the character of the game, as the knight will go to c4 and will be captured.
6. c2c3  6... b8c6  7. a2a3 A rare move. 7.f4 transposes to the position discussed in the first game of the match. 7... f8e7  8. c1e3 An opening novelty that was played instantly. The idea is to hold the pawn on d4 firmly, as it's the important stronghold in White's position. Development can be completed by moving the knight to f4, also preparing an attack on the kingside. White has a space advantage, a characteristic of this pawn structure, so if he manages to finish development the attack can be very dangerous.